Anode for iron plating



, tile form,

Patented Mar. I 1, 1932 UNITED STATES PATENT T OFFICE JOHN R. CAIN, OFWASHINGTON, DISTRICT or COLUMBIA, ASSIGNOR TO THE RICHARD- soN COMPANY,OF LocKLAN OHIO, A CORPORATION OF OHIO ANODE FOR IRON PLATINU- NoDrawing.

My invention relates to the production of anodeswhich are suitable forthe production of electrolytic iron which is soft and workable insteadof being brittle.

The problem of production of electrolytic iron involves among otherthings, the fact that past commercial practices have resulted inproducing this iron in a brittle, non-ducso far as they have come to myattention.

In a series of experiments aimed at discovering the reasons for thisbrittleness, and after elimination by such experiments of a number ofpossible causes, I have discovered thatwith ferrouschlorideelectrolytes, kept at a temperature close to the boiling point thereof,and controlled as to hydrogen ion content during the electrolyticdeposition of metal, that a soft white electrolytic iron will beproduced.

In a co-pending application, Serial No. 238,232, I have described anelectrolytic process producing soft iron involving the continuouscontrol of the hydrogen ion content of a ferrous electrolyte which iskept at a temperature close to the boiling point thereof during use. Myanodes as here claimed are particularly adapted for use in that process.

I do not wish to limit the application of my present invention, whichlies in the composition of the anode used by me to maintain the bathfree of acid, to the specific type of electrolyte with which it may beemployed.

The essence of my invention is the employment of a control substance aspart of or as all of the anode. This invention has many advantagesbesides the reduction of acid development and content, and theconsequent diminution of the hydrogen ion concentration as an activefactor at the cathode, where the iron is being deposited.

I prefer to use ferrous sulphide (FeS) for the control substance. Forone thing, ferric sulphide is an inexpensive natural substance which canbe readily fused in a container, and

when so fused, passes readily to the desirableferrolis condition, andcan be employed to retain masses of 1ron or steel scrap, and of ironores and sponge iron. Also, it has the 1927. Serial No. 173,793.

I do not wish to be bound to the correctness thereof, since thereactions in the baths used as electrolytes by me, are not easy totrace.

I will, in the description of a typical example of my invention,however, refer to my theory of reactions, and of cause and effect,,withthe understanding that there may be other factors entering into theexplanation of the surprising results obtained, which factors I have notas yet determined. f

-With the aim of producing a deposit of soft and ductile electrolyticiron upon a suitable cathode, in my typical example, I employ .a cathodein the form of a sheet of electrolytic iron of the type produced by me,or

resulting from annealing and pickling of electrolytic iron produced byother processes. I employ as an electrolyte a bath of ferrous chloridein water, having 100 grams of iron per liter. This is not asconcentrated a solution as I could use with ood results, but willsuflice for excellent wof'k This electrolyte I maintain at between 90and 95 degrees Centigrade, and I also provide for filtering theelectrolyte during use, for reasons to be explained.

If an anode of iron were used, it would be necessary to addferroussulphide or some other neutralizer or conditioner to the bath,from time to time to obtain the efiects that I obtain, and it is theobject of my invention to provide an anode which automatically takescare at least in part of the iron sulphide addition, and continuously.

S. The sulphide may also neutralize sulphur or chlorine acids directlyformed, but I believe that its chief function is to prevent theformation of acid which would otherwise resut from the hydrolysis offree ferric chlor1 e.

A variety of processes may be used in producing the iron sulphidebearing anodes. One way will be to employ commercial iron sulphide,which will be mixed in withpieces of various sizes of iron and steelscrap, sheet clippings, borings, or other iron scrap material, in asuitable dish, which may be formed of ingot iron sheets. The dish isthen placed in a furnace and heated sufficiently to sinter the mass. Ifferrous sulphide is .used, this fusion or sintering will be very rapid;but if the ferric form is employed, I prefer to prolong the heatinguntil all or nearly all of the sulphide is present in the ferrous form.If it is not desired to use the dish as a part of the anode, thesintered or fused mass can be removed and will be self supporting to adegree suflicient to permit of its being used as an anode. I may preferto use a cast anode member of iron sulphide alone, or a com- .tpositemember of iron sulphide and a preformed iron core. FusedFeS has a goodconductivity, and is quite effective in producing the correct neutralityof electrolyte required for depositing ductile iron.

So far I have not obtained effective results where the electrolyte isused cold.

Another form of the anode is made by using a dish of iron or steel, andfusing the iron sulphide into it, alone, in which case the dish forms apart of the anode, or the molded block may be removed therefrom and usedby itself. Or I ma make a composite anode including oxides 0 iron thus:The iron sulphide may be liquefied by the use of an oxyacetylene torch,and the ferrous oxide of iron, or other iron, stirred into the mass,after which it is permitted to set.

ing iron which consists of fused ferrous sulphide.

2. A solid unitary anode for use in plating iron which contains ironsulphide as an essential ingredient of the unitary mass.

3. A solid anode for use in plating iron which contains ferrous sulphideas an essential ingredient, together with iron the several ingredientsformlng a unitary, conductive mass.

4. An anode for use in platin iron which contains iron sulphide, andiron caring materials held in said sulphide as abinding agent.

5. An anode for use in plating iron which is formed -of a mass of ironbearing materials with sintered iron sulphide.

' JOHN R. CAIN.

I find that the conditioning of the electrolyte by the use of sulphideof iron in the anode itself, is much preferable to the use of same asother than part of the anode. The electrolyte not only becomes morequickly conditioned, but also keeps the proper hydrogen ionconcentration longer after the conditioner has been removed.

I find also that the sulphide anodes may be used only partof the time,and can be replaced by'iron anodes without sulphide, periodically,during a plating process without having ill effects upon the softness ofproduct.

With another electrolyte the neutralizer would, perhaps, have to bedifferent in composition, and I do not wish to limit my invention tothis one substance in its broader ascts. I may without ill effects, in aplating apparatus having a continuous circulatory system for theelectrolyte, establish a series of

